1. Field of the Invention
The present invention generally relates to a single-chip, multi-functional optoelectronic device and method for fabricating same, and more particularly to the growth and fabrication of an optoelectronic device in which multiple elements are physically integrated on a single semiconductor chip. More specifically, using suitable materials, growth substrates, growth sequences and fabrication techniques, an optical emitter, detector and modulator are integrated onto a single semiconductor chip. The device method of the present invention can be utilized in any number of technical applications--for example, of a repeater site in a fiber optical work system.
2. Description of the Prior Art
The state of current technology is such that emitters, detectors and modulators must each be made from different materials and material structures in order to operate at the same energy. Thus, optoelectronic devices that require more than one of these functions (i.e., emission, detection or modulation) can only be fabricated in essentially two ways. Either separate components are combined into a single package, or regrowth techniques are used to produce the separate functions on a single element (that is, a single chip).
Currently, there are no economical methods or techniques that can be utilized to produce a single-chip device that performs all three functions of emissions, detection and modulation. Current technology resorts to either regrowth techniques, impurity-induced disorder techniques, or techniques that combine multiple elements into a single package. Large, bulky interconnections are required in order to combine separate elements into a single package. Not only are the optical interconnections bulky and heavy, but they also significantly reduce the amount of power transmitted between the individual elements. Both the regrowth technique and the impurity-induced disorder technique are time-consuming and money-intensive due to the multiple processing steps that are required.
Recent studies of strained-layer quantum well structures have shown unusual behavior in that the energy which the material absorbs first increases with increasing reverse biases, and then decreases with still further increases in the reverse bias. In the latter regard, see the following: Richard L. Tober and Thomas B. Bahder, "Determining the Electric Field in [111] Strained-Layer Quantum Wells", Appl. Phys. Lett. 63 (17), (1993); Richard L. Tober, Thomas B. Bahder and John D. Bruno, "Characterizing Electric Fields in [111] B InGaAs Quantum Wells Using Electric Field Modulated Photoluminescence and Reflectance Techniques", accepted for Journ. Electron. Mater. (1995); Thomas B. Bahder, Richard L. Tober and John D. Bruno, "Temperature Dependent Polarization in [111] InGaAs-AlGaAs Quantum Wells", Phys. Rev B15, 50,(7), (1994); and Thomas B. Bahder, Richard L. Tober and John D. Bruno, "Pyroelectric Effect in Semiconductor Heterostructures, Superlattices and Microstructures", 14(2), (1994).